If you're frequently fatigued or suffer from low energy—despite getting adequate sleep—it's time you learned a thing or two about your mitochondria. They play an enormously important role in the way your body stores and uses energy.
So what are mitochondria, and what role do they play in your health? Mitochondria are organelles present in every cell in your body that work to produce the energy for that cell and, by extension, for the organ in which that cell resides. Depending upon how metabolically active the organ is, there will be varying numbers of mitochondria in each cell. For example, the muscles and the brain are very metabolically active, so they contain many mitochondria.